Two things I would really like for Maps are:
1) An undo function (CTRL-Z). Too often I accidentally click on “reveal all” or cover up a part of the map when I had intended to reveal it, or I accidentally delete a PC icon instead of a dead monster’s icon. It would be great if I could just CTRL-Z undo those mistakes!
2) Layers or some other way to hide/reveal things like secret doors. Instead of having to draw a bad S on the screen, it would be nice to have layers with the DM version underneath the player map so I can reveal a secret door (or something else thats on the DM map but not the player one).